Guild Wars 2

TL:DR – Master Maintenance Oil (and likely all similar Maintenance Oils) grants 6% Vitality/4% Toughness, not the 4% Vitality/6% Toughness shown in the tooltip.

Lengthier explanation – While tweaking a character’s build, I noticed that my Precision was a few points higher than I expected. It wasn’t much, but every calculation I made indicated that it was off. I tried altering my equation to account for the WvW health bonus, treating it as though it were pure Vitality, but that didn’t give me the correct result. After testing various other things, I tried an equation which swapped the bonuses from Master Maintenance Oil and arrived at the Precision value displayed in the Hero Panel.

I then switched to a different character, checked the base Precision, Vitality and Toughness values, applied Master Maintenance Oil and checked the math against what was displayed. The value of Precision shown in the Hero Panel didn’t match what it should have been, but if I swapped the percentage bonuses listed in the Oil tooltip (6% Vitality instead of 4%, and 4% Toughness instead of 6%), my calculation matched what was on-screen.